If N=(6+√34)7, then digit at unit's place of (N(1- N )10,( where . denotes fractional part function ), is equal to

Question

If N=(6+√34)7, then digit at unit's place of (N(1- N )10,( where . denotes fractional part function ), is equal to (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

N=(6+√34)7=I+f (6-√34)7=f' f+f'=1 f'=1-f N(1- N )=N(1-f) =(6+√34)7(6-√34)7=27 270 unit's digit =4

Q. If $N = (6 + 34)^{7}$ , then digit at unit's place of $(N (1 -$ ${N})^{10}, ($ where ${.}$ denotes fractional part function $)$ , is equal to